This invention relates, in general, to vapor compression systems, and more particularly, to a vapor compression system having an evaporator with at least one feed line for flowing heat transfer fluid into a coil having multiple orifices.
In a closed-loop vapor Compression cycle, heat transfer fluid changes state from a vapor to a liquid in the condenser, giving off heat to ambient surroundings, and changes state from a liquid to a vapor in the evaporator, absorbing heat from the ambient surroundings during vaporization. A typical vapor compression system includes a compressor for pumping heat transfer fluid, such as a freon, to a condenser, where heat is given off as the heat transfer fluid condenses into a liquid. The heat transfer fluid then flows through a liquid line to an expansion device, where the heat transfer fluid undergoes a volumetric expansion. The expanded heat transfer fluid then flows into an evaporator. The evaporator includes a coil having an inlet and an outlet, wherein the heat transfer fluid is vaporized at a low pressure absorbing heat while it undergoes a change of state from a liquid to a vapor. The heat transfer fluid, now in the vapor state, flows through the coil outlet and exits the evaporator. Upon exiting the evaporator, the heat transfer fluid then flows through a suction line and back to the compressor.
In one aspect, the efficiency of the vapor compression cycle depends upon the time required to charge the evaporator, that is the time required to fill the coil within the evaporator with the heat transfer fluid. In general, vapor compression systems charge the evaporator by flowing heat transfer fluid through the coil inlet, through the length of the coil and out through the coil outlet. The heat transfer fluid fills the length of the coil all by entering through only one orifice, that is, the coil inlet. Charging the evaporator by forcing heat transfer fluid through only one orifice, the coil inlet, takes a substantial amount of time. Additionally, by locating that orifice at the entrance of the coil, the heat transfer fluid is forced to fill the coil in a direction from the coil inlet to the coil outlet. This causes the temperature of the coil surface surrounding coil inlet to become much cooler than the temperature of the coil surface surrounding the coil outlet, while the evaporator is charging. Since the temperature of the coil surface is not constant throughout the length of the coil, the evaporator may not absorb heat as efficiently from the ambient surroundings.
Accordingly, further development of vapor compression systems, and more specifically, vapor compression systems which charging an evaporator by forcing heat transfer fluid through only one orifice, is necessary in order to decrease the amount of time required to charge an evaporator and increase the efficiency of the evaporator.
According to one aspect of the present invention, a vapor compression system is provided. The vapor compression system includes a compressor for increasing the pressure and temperature of a heat transfer fluid, a condenser for liquefying the heat transfer fluid, and an expansion device having an inlet and an outlet. The vapor compression system also includes an evaporator for transferring heat from ambient surroundings to the heat transfer fluid. The evaporator includes a main distributor having an inlet, a first outlet, and a second outlet, a coil, the coil having an inlet connected with the first outlet of the main distributor, an outlet, and at least one opening, wherein the opening is located on a surface of the coil between the inlet and the outlet, and a feed line connecting the second outlet of the main distributor to the coil opening. The vapor compression system includes a discharge line connecting the compressor to the condenser, a liquid line connecting the condenser to the inlet of the expansion device, a saturated vapor line connecting the outlet of the expansion device to the inlet of the main distributor, and a suction line connecting the outlet of the coil to the compressor.
According to another aspect of the present invention, a method for operating a vapor compression system is provided. The method includes, providing an evaporator for transferring heat from ambient surroundings to a heat transfer fluid, the evaporator comprising at least one coil, the coil having an inlet, an outlet, and at least one opening, wherein the opening is located on a surface of the coil between the inlet and the outlet, and flowing the heat transfer fluid through both the coil inlet and the coil opening.
According to yet another aspect of the present invention an evaporator for transferring heat from ambient surroundings to a heat transfer fluid is provided. The evaporator includes a main distributor for receiving heat transfer fluid, at least one coil, the coil having an inlet connected with a first outlet of the main distributor, an outlet, and at least one opening, wherein the opening is located on a surface of the coil between the inlet and the outlet of the coil, and a feed line connected with a second outlet of the main distributor and the coil opening.